introduction to winspice

8/19/2019 Introduction to WinSpice

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Analog Electronics Laboratory 1


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Introduction• SPICE: Simulation Program with Integrated

Circuit Em hasis

• SPICE is program that simulates electroniccircuits on your PC

• You can view any voltage or current waveform

in your circuit. SPICE calculates these voltages

or versus frequency (AC Analysis).

• SPICE was develo ed at Universit of California Berkeley.

• SPICE3 is the latest version that UCB offers.



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SPICE VersionsVarious SPICE based circuit simulators are available:

Commercial:

- HSpice- Spectre Widely used in Industry

-

- PSpice

Free:

- WinSpice

- LTSPICE

- ng p ce



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How SPICE Works?SPICE operates like this:

. .

extension) called a netlist OR draw the circuitusing graphical symbols on a schematic page.

2. Run a simulation. SPICE reads the netlist andthen performs the requested analysis: AC, DC,or TRANSIENT RESPONSE.

3. Plot or print the simulation results

In this lab we will be using the text file

o epa ocumen o escr e e c rcu



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SPICE file consists of three parts.

• Data Statements describe thecom onents and the interconnections.

• Analysis Statements tell SPICE what.

• Output Statements specify what outputs

.



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’Title statement

circuit descriptionPower Supplies / Signal Sources

Model Statements

Analysis Requests

Output Requests


n ne


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’

• e rst ne s a ways t e an can conta n any

information.

•

• Extra spaces are ignored.

• Comment statements must begin with an asterisk (*) andare ignored by SPICE except *DEFINE and *INCLUDE.

• The datum (ground) node must be named '0'.

• e or er o t e rema n ng nes s ar trary.• If you want to continue a statement to the next line, then

use a "+" si n at the be innin of the next line.



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SIMPLE TWO RESISTOR VOLTAGE DIVIDER

V1 1 0 10*Connect a DC power supply Vin between node

*

R1 2 1 10K

*Connect a 10K resistor between node 1 and 2

R2 2 0 10K

*Connect a 10K resistor between node 2 and 0

.TRAN 1NS 100NS 0NS

*Perform Transient Analysis from 0ns to 100ns

w t a step o ns.PLOT TRAN V(2)

*Plot the Voltage at node 2 of transient analysis


.

*End of SPICE File


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Output



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Representing basic circuitelements

• An element line specifies- The circuit nodes to

Letter DescriptionR Resistor

w c t e e ement s connecte .

-Values of the parameters

apac or

L Inductor

I Independent current source

characteristics.

• The first letter of the element

V Independent Voltage source

D Diode

name specifies the element type. Q Bipolar Junction Transistor(BJT)

M MOSFET



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Scale Factors

•A number field may be an

- . . , ,

a floating point field(3.14159), either an

n eger or oa ng po n

number followed by an

integer exponent (1e-14,2.65e3), or an integer or a

floating point number

scale factors.



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Representing basic circuit

elements

Resistors

• Rxxx is the name of the resistor in circuit.• an are t e two e ement no es.

• VALUE is the resistance (in ohms).

For example:



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Capacitors

enera orm :

Cxxx N+ N- VALUE

Cxxx is the name of the resistor in circuit.

N+ and N- are the two element nodes.

VALUE is the capacitance in Farads.The o tional initial condition is the initial time-zero value o

capacitor voltage.

Example: C1 32 33 1U


CSHUNT 50 51 10U IC=3 V


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Inductors

Lxxx N+ N- VALUE

xxx s e name o e res s or n c rcu .

N+ and N- are the two element nodes.VALUE s t e n uctance n Henr es.

The (optional) initial condition is the initial (time-zero) value of

n uctor current n mps t at ows rom +, t roug t e n uctor,to N-.

Exam le: L1 32 33 1U


LSHUNT 50 51 10U IC=13.1MA


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Voltage source: Vname N+ N- DCValueCurrent source: Iname N+ N- DCValue

N+ is the positive terminal & N– is the negative

terminal.DCValue gives the value of the source.

The name of a volta e and current source must

start with V and I, respectively.



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Independent Sources

VXXXXXXX N+ N-


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Independent Sources (Cont’d)

+ - > < <

>>

IYYYYYYY N+ N-

• DC/TRAN is the DC and transient analysis value of the

source. If the source value is zero both for DC and transient

analysis, this value may be omitted. If the source value is

time-invariant (e.g., a power supply),then the value mayop ona y e prece e y e e ers .

• ACMAG is the AC magnitude and ACPHASE is the AC

phase. The source is set to this value in the AC analysis. If

s om e o ow ng e eywor , a va ue ounity is assumed. If ACPHASE is omitted, a value of zero is

assumed. If the source is not an AC small-signal input, the


.


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Examples

ISRC 23 21 AC 0.333 45.0

. .



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Pulse Source: PULSE()

General form:PULSE(V1 V2 TD TR TF PW PER)

ere

V1=initial value

V2= ulsed value

TD=delay time

TR=rise time

TF=fall time

PW=pulse width

=



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Exam leVIN 3 0 PULSE(-1 1 2NS 2NS 2NS 50NS 100NS)PULSE V1 V2 TD TR TF PW PER



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Sin Source: Sin()

General form:SIN(VO VA FREQ TD Theta)

=o set

VA=amplitude

=

Theta=Damping Factor

Example:VIN 3 0 SIN(0 1 100MEG )



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EXAMPLE

•V1 is the amplitude

• s e o se vo age•To is the time delay

•fo is the frequency


•a is damping factor in perseconds


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Device Models• For Semiconductor devices we use device models

• Each model specify different parameters of a device

This line appears any where in your netlist

D/Q/Mxxx N1 N2 N3.. MODName

Then any where you write

For diode.MODEL MODName D (IS= N= Rs= CJO= …..)

or

.MODEL MODName NPN/PNP (BETA= VA= CJBE=……)

For NMOS/PMOS MOSFET =. ……

N1, N2, N3 are the terminals of the device:

N1, N2 are Anode and Cathode nodes of Diode respectively

N1 N2 N3 are the Collector Base Emitter nodes of BJT res ectivel .

N4 is the (optional) Substrate node N1, N2, N3, N4 are the Drain, Gate, Source and Body nodes of MOSFETrespectively.



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Analysis Request lines. tatement

.DC SRCNAME START STOP STEP

.

STOP are the starting and ending value, respectively.STEP is the size of the increment.

Example: .DC V1 1 20 2.5

When the Start and Stop values are identical (and the Step isnon-zero), .DC command produces only one value

A DC anal sis is automaticall erformed rior to a transient

analysis with capacitors open circuit inductors short circuit and all time varying sources set to zero to determine the transient



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.Another form is

. <

START2 STOP2 INCR2>

.DC VDS 0 10 .5 VGS 0 5 1

to be swept from 0 Volts to 10.0 Volts inincrements of 0.5 Volts. For each increment in the

secon source, rst source s swept over ts range.



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Example

NMOS VDS-ID CURVES

VDUM 4 3 0VGS 2 0 1

= = .

.MODEL MN NMOS (LEVEL=1 TOX=2.6N VT0=0.3 GAMMA=0.2

+PHI=0.6 U0=250 LD=0.025U CJ=8E-4 CJSW=8E-12

+CGSO = 3.365E-10 CGDO=3.365E-10 LAMBDA=0.2)

.DC VDD 0 5 0.01 VGS 0 0.7 0.1

.PLOT DC I(VDUM)

.END



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Output



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Transient Analysis

.TRAN

.TRAN TSTEP TSTOP

.

time, and TSTART is the initial time. If TSTART isomitted, it is assumed to be zero. UIC (use initialconditions indicates that the user does not want SPICE tosolve for the quiescent operating point before beginningthe transient analysis. SPICE then uses the values specified

using IC=... on the various elements as the initial transientcon t on.

Example :

.TRAN 1NS 100NS

.TRAN 1NS 1000NS 500NS



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This statement is used to specify the frequency (AC) analysis. The format is asfollows:

.

.AC DEC ND FSTART FSTOP

.AC OCT NO FSTART FSTOP

LIN stands for a linear fre uenc variation.

DEC and OCT for a decade and octave variation respectively.

NP stands for the number of points and ND and

NO for the number of frequency points per decade and per octave respectively.FSTART and FSTOP are the start and stopping frequencies in Hertz.

Examples:

.

.AC DEC 10 1K 100MEG

.AC LIN 100 1 100HZ



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.OP: Operating Point Analysis

• General form:

.

determines the DC operating point of the

circuit with inductors shorted and

capacitors opened. The output of thisanalysis is automatically printed. i.e. no

explicit print command is required



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OUTPUT STATEMENTS.PRINT and .PLOT

.PRINT TYPE OV1 OV2 OV3 ...

.PLOT TYPE OV1 OV2 OV3 ...

.PLOT DC V(1,2) V(3)

.PLOT TRAN I(V1)

•In the original SPICE version (and the one that we will use

in the lab) we must place a DC dummy voltage source i.e.

, .

•We then use I(Vdum) to print or plot current through the

terminal is taken as positive.

•In one .PLOT statement OV1 OV2…can be current or


voltage variables but not both.


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Example

+15V

CCR133k

RC1. 2k

+

u

+

CB10uF Q1

NPN

+CE

100uF

+

-

VI NRL1kR2

18k RE1. 2k


E l ( ’d)


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Example (cont’d)

.MODEL QMOD NPN (Is=6.734f Xti=3 Eg=1.11 Vaf=74.03 Bf=100+Ne=1.259 Ise=0 Ikf=66.78m Xtb=1.5 Br=.7371 Nc=2 Isc=0 Ikr=0+Rc=1 Cjc=3.638p Mjc=.3085 Vjc=.75 Fc=.5 Cje=4.493p Mje=.2593

+Vje=.75 Tr=239.5n Tf=301.2p Itf=.4 Vtf=4 Xtf=2 Rb=10)

VDUM 12 10 0

RC 10 9 1.2k

RE 7 0 1.2K

R1 12 8 33K

R2 8 0 18K

CE 7 0 100UCB 6 8 10U

CC 9 11 10U


RL 11 0 1K

E l ( ’d)


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Example (cont’d)

* Note the AC keyword in the above line which specifies that the

* VSIN has magnitude 1 for the AC analysis. Omitting the AC

*

*hence will result in incorrect output for the AC analysis

.OP

.TRAN 100N 1M

.PLOT TRAN V(6) V(11)

.AC DEC 100 1 1000MEG

.PLOT AC V(11)

.



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Out ut: TRAN anal sis



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Out ut: AC anal sis



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Out ut: OP anal sis



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Circuit Restrictions

• Every node in the circuit

defined for SPICE musthave a DC path to 100mA

+

1uFgroun no e .

• A DC path to ground

can be through a0

res s or, n uc or orvoltage source but notthrough a capacitor or

12 +1uF

.

• In figures node 1 doesnot have a valid DC path -

10V 1uF 1uF


0


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Circuit Restrictions

• SPICE does not permit any loop to consist

sources.

1uH

+

-

SPICE does not permit series combination of

ca acitors and current sources.



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Subcircuits• A comp ex e ectron c c rcu t o ten conta n severa components, or

subsections of circuitry that are identical to each others

• Examples

-

- logic gates

• SPICE allows a user to create subcircuits that are created once andthen can be inserted into a larger system at as many places as desired.

• A subcircuit definition starts with .SUBCKT

. < , ….>

SUBNAM is the subcircuit name N1,N2,N3…are the node numbers in

cannot contain datum(0) node.Examples:

.SUBCKT OPAMP 1 2 3


.SUBCKT INV IN OUT VCC


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Subcircuits cont’d • A subcircuit can contain other subcircuits, device modelsand subcircuit calls.

• na ys s an output nes suc as . , . , . ,

cannot appear within a subcircuit definition• Any device models or subcircuit definitions included as

par o a su c rcu e n on are s r c y oca .e. sucmodels and definitions are not known outside thesubcircuit definition.

. ,with the exception of 0 (ground) which is always global.

• Local nodes can be made global by using the .GLOBAL.



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Calling Subcircuits• The last statement in a subcircuit must be

.ENDS

,

must be given in the .ENDS to specify which subcircuitdefinition has been ended.

,subcircuit call

X**** N1, SUBNAM

, … joined to subcircuit nodes specified in the .SUBCKT linein exactly the order. SUBNAM is the name of the

Examples:X1 6 7 8 OPAMP



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Example

+5V

RC3RC2RC1

RB3100 ohms

RB2100 ohms

1k1k1k

RB1100 ohms

+

-

PULSE0- 5V

3NPN

Q2NPN

NPN



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Example (cont’d)3 CASCADED INVERTERS

VSUPPLY VCC 0 5

VIN 1 0 PULSE (0 5 0 0 0 10N 20N)

X1 1 2 VCC INVERTER

X2 2 3 VCC INVERTER X3 3 4 VCC INVERTER

.SUBCKT INVERTER IN OUT VCC

Q1 OUT BASE 0 NPNMOD

RC VCC OUT 1K

.MODEL NPNMOD NPN(BF 100)

.

.TRAN 1N 100N

.PLOT TRAN V 1 V 4


.END


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OUTPUT


D l d


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Download

• Download and install WinSpice. Its Free

www.wins ice.com

• To check, double click on WinSpice icon, acommand window will o en then o to

File>Open>C:\Program Files\ Ouse

Tech\WinSpice\Examples and then double clickon any “.cir” file.

• WinSpice also has a very well written User

anua . o to start menu>Programs>WinSpice>User Manual



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. n p ce ser anua

2. “Spice and PSpice” an appendix chapter“ ”n ec ron c ev ces an rcu s y

Theodore F. Bogart.

• n ese s es we ave presen e on y asmall subset of all SPICE capabilities. For

WinSpice User Manual.


introduction to winspice

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